This invention provides a blend of two different silicone resins precondensates. More particularly, it provides such a blend with aluminum flake for good adhesion to a substrate and good non-stick performance in cooking foods.
It is desirable to provide cookware with release or non-stick coatings so that food residues can be removed easily as the cookware is cleaned. High performance non-stick coatings generally include fluorocarbon resins such as polytetrafluoroethylene and require curing temperatures above 290.degree. C. Silicone resin (or polysiloxane precondensate) coatings are less expensive and can be cured at lower temperatures but traditionally have characteristics which cause the coatings not to last as long as or perform as well as fluorocarbon resin coatings on cookware.
Prior attempts to provide silicone resin coatings, especially as single-layer coatings, have not given as high a level of performance as is desirable for certain cookware applications. Multilayer coatings are inherently more expensive to apply than single-layer coatings.
U.S. Pat. No. 4,369,279 (Jan. 18, 1983)--Emerick provides a single-coat silicone resin, epoxy coating composition containing a small amount of fluorocarbon polymer and curable at 107.degree. C.
U.S. Pat. No. 4,181,686 (Jan. 1, 1980)--Vassiliou and its divisions U.S. Pat. Nos. 4,180,613 and 4,183,998 concern silicone resin coatings containing a relatively tough and sticky particulate organic modifier to provide improved craze resistance for thicker coatings.
U.S. Pat. No. 4,223,069 (Sept. 16, 1980)--Berghmans provides a three-coat system including an epoxy primer and different types of silicones having specified hydroxyl contents in the intermediate and topcoats.
U.S. Pat. No. 4,252,702 (Feb. 24, 1981)--Wald concerns a silicone- and epoxy-containing coating composition.
U.S. Pat. No. 4,477,517 (Oct. 16, 1984)--Rummel concerns a baking pan with a multilayer coating including a primer containing a silicone resin and a silicone oil and a topcoat containing a silicone resin, colloidal silica and flake pigment.
Each of these patents are incorporated by reference herein.